Updated to latest pkg dep

This fixes an issue with returning an errors from the JSON helper
functions.

README.md

@@ -1,6 +1,6 @@
 package pure
 ============
-<img align="right" src="https://raw.githubusercontent.com/go-playground/pure/master/logo.png">![Project status](https://img.shields.io/badge/version-5.0.2-green.svg)
+<img align="right" src="https://raw.githubusercontent.com/go-playground/pure/master/logo.png">![Project status](https://img.shields.io/badge/version-5.0.3-green.svg)
 [![Build Status](https://travis-ci.org/go-playground/pure.svg?branch=master)](https://travis-ci.org/go-playground/pure)
 [![Coverage Status](https://coveralls.io/repos/github/go-playground/pure/badge.svg?branch=master)](https://coveralls.io/github/go-playground/pure?branch=master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/go-playground/pure)](https://goreportcard.com/report/github.com/go-playground/pure)

go.mod

@@ -1,6 +1,6 @@
 module github.com/go-playground/pure
 
 require (
-	github.com/go-playground/pkg v0.0.0-20190513235050-6cd3d118a436
+	github.com/go-playground/pkg v0.0.0-20190522230805-792a755e6910
 	gopkg.in/go-playground/assert.v1 v1.2.1
 )

go.sum

@@ -8,6 +8,8 @@ github.com/go-playground/pkg v0.0.0-20190513234448-af45a46936e9 h1:SMJgXE/ouCVX2
 github.com/go-playground/pkg v0.0.0-20190513234448-af45a46936e9/go.mod h1:Wg1j+HqWLhhVIfYdaoOuBzdutBEVcqwvBxgFZRWbybk=
 github.com/go-playground/pkg v0.0.0-20190513235050-6cd3d118a436 h1:5FwEqhdQHGB+01ryvrBy2Uig1cYQ/U4GVTT6fVSEOhA=
 github.com/go-playground/pkg v0.0.0-20190513235050-6cd3d118a436/go.mod h1:Wg1j+HqWLhhVIfYdaoOuBzdutBEVcqwvBxgFZRWbybk=
+github.com/go-playground/pkg v0.0.0-20190522230805-792a755e6910 h1:h7toKaxfg9ttAloheYEndInQhXwOC/Knglt0L5MMVCM=
+github.com/go-playground/pkg v0.0.0-20190522230805-792a755e6910/go.mod h1:Wg1j+HqWLhhVIfYdaoOuBzdutBEVcqwvBxgFZRWbybk=
 github.com/go-playground/pkg v1.0.1 h1:EsBCgjDTrlaLCflFChT2Q/M4unQQS6DnBDvHTA+fVAI=
 gopkg.in/go-playground/assert.v1 v1.2.1 h1:xoYuJVE7KT85PYWrN730RguIQO0ePzVRfFMXadIrXTM=
 gopkg.in/go-playground/assert.v1 v1.2.1/go.mod h1:9RXL0bg/zibRAgZUYszZSwO/z8Y/a8bDuhia5mkpMnE=